Telecommunication housings shield, secure, and protect telecommunication network cables and components from its surroundings. These housings, often constructed of metallic materials, are usually low-lying and commonly installed in space-limited environments. These environments include underground enclosures such as manholes where flooding can occur. In such environments, these metallic telecommunication housings are subjected to moderate to severe corrosion due to issues of galvanic corrosion and corrosive media, and to other forms of corrosion relating from immersion and stray ground currents.
There is a significant need for corrosion protection for these metallic telecommunication housings. One method of corrosion protection currently employed for immersed and intermittently immersed metallic telecommunication housings is sacrificial cathodic protection using sacrificial anodes. In this method, a potential inhibiting corrosion develops between the protected metallic housing and a metallic substance, (the sacrificial anode), that contains a lower galvanic potential than that of the protected metallic housing. The potential difference between the protected metallic housing and a properly selected sacrificial anode prevents the corrosion reaction of the protected structure at the expense of corroding the sacrificial anode. While this can be an effective method in protecting the metallic housing, the sacrificial anode must be regularly maintained and the surrounding environment is affected by high levels of metallic corrosion products released by the sacrificial anode into the immersion environment (electrolyte). Regular maintenance includes replacing the sacrificial anode. In some instances, when performing maintenance the standing water in the enclosed environment is removed. Typically this water is pumped into storm sewers. This has caused an environmental issue of contaminating the ground and water with the metallic corrosion products released by the sacrificial anode found in this standing water.
Another method of corrosion protection currently employed for immersed and intermittently immersed metallic telecommunication housings is impressed current cathodic protection using a permanent anode. In this method, a potential inhibiting corrosion is impressed between the protected metallic housing and a metallic substance, (the permanent anode). The potential difference between the protected metallic housing and a properly selected permanent anode prevents the corrosion reaction of the protected structure at the expense of power. Access to external power sources are needed and take up valuable space in the confined environment. Also when AC power is provided additional components such as a rectifier to convert the power to DC for use in the impressed current cathodic protection system is needed. Again requiring more equipment in a congested environment.
Another method of corrosion protection is the use of a barrier coating. The barrier coating, when applied directly onto the electronics housing, creates a seal around the housing, protecting it from the surrounding, corrosive environment. This method can be effective if the housing is barrier coated before the housing is subjected to a corrosive environment. Once corrosion has begun on the housing however, creating an effective bond on the metallic surface is difficult. Many of the metallic housings that require corrosive protection have already been placed in corrosive environments and as such effective barrier coating is difficult to achieve. Congested installation sites may further complicate the field application of a barrier coating. The need for a retrofitable solution is high.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the telecommunications industry for an effective, low maintenance and low replacement method of protecting existing and new metallic telecommunication housings from corrosion. Furthermore, there is a need to avoid the use of additional components and power utility drops in the space limited environment that overcomes the limitations noted above.